Motion-picture-projecting apparatus



Nov. 4, 1924. 1,513,920

. E. MECHAU MOTION PICTURE PROJECTING APPARATUS Filed Sept 19 1922 2 Sheets-Sheet l jnvenior M u/CI NOV.4,192 4, 1,513,920

' E. MECHAU.

MOTION PICTURE PROJECTING APPARATUS Filed Sept 19, 1922 2 Sheets-Sheet 2 nvenlo r Patented Nov. 4, 1924.

UNITED STATES PATENT OFFICE- EIIL KECHAU, OF RASTATT,.GERMANY.

Y HUIION-PIOTIl'BE-PBOJECTING' APPARATUS Application filed iepteznber 19, 1922. Serial No. 589,200.

order to revent the film from fire, and in.

which a evice is employed for protecting the film against the beam of light before it gets ignited. This device may be of any suitable kind provided that it is adapted to interru t the access of the beam of light to the film in a given moment.

The general object of myinvention is to provide very simple and reliable means in such apparatus for actuating the protecting devlce, and which means may be employed in combination with various known motion-picture-projecting a paratus so that my invention may be added to various existing apparatus to effect the desired pre vention from fire.

My invention consists of a member which is adapted to swim on a fluid and to engage with the mentioned device for protecting the film against the beam of light, and of a feeding device which can be set in action by suitable means, for instance by the film driving gear or by a roll driven from the moving film. When the speed of the film through the apparatus is above a predetermined value, this feeding device draws up more fluid under the floating member than can flow back, whereupon the floating member falls and thereby sets the device for protecting the film against the beam of light out of o oration. Similarly when the speed of the 1m through the apparatus is below this predetermined value, the feeding device draws up less fluid, whereupon the floating member rises again and thereby sets the projecting device into operation.

The fluid drawn up may either be fed by the feeding device into an adjacent chamber or applied as a weight on to the floating member. The latter arrangement ensures a high security especially if the fluid is a heavy one as for instance quicksilver.

I have shown in the drawing one specific form of apparatus embodying my invention, but I desire to be understood that my invention, as set forth in the annexed claims, is not dependent of any particular projecting apparatus or of the exact details of construction shown and described, for

obvious modifications will occur to a person skilled in the art.

Figure 1 is a section of so much of a m'otion-picture-projecting apparatus as is necessary to show my improvements, and

Figure 2 is a perspective view of the same.

Referring to the fi res, especially to Figure 1, the dotted ine A B C D lets show the path of rays of light through the apparatus. A source of light emitting a beam of light to illuminate a film l is to be thought to the left of an opening 2 which can be closed by means of a shutter 3 mounted on a bent lever 4, thelatter being movable about a shaft 5. A spiral spring 6 is connected to the bent lever 4 1n such a manner that the shutter 3 tends always to close the entrance opening 2 for the illuminating beam of light. On the upper end of the bent lever 4 is fitted an arm 7 having a hook formed end.

In an entirely closed chamber 8 filled partly. with quicksilver a paddle wheel 9 is placed revoluble about an axis 10 on which is also fixed a roll 11. This roll 11 and consequently the paddle wheel 9 is set into rotation by the film 1 moving through the projector gate of the apparatus. Further in the chamber 8 is situated a sheave 12 with a shaft 13, the latter being guided in such a manner that the sheave 12 is only movable in the direction of its shaft 13. The sheave 12 will swim on the quicksilver by stopping paddle wheel'9; if the latter by moving film 1 rotates, it draws up quicksilver under the sheave 12 and brings it up to the same. Of this quicksilvera part flows back on the walls surrounding the sh ave 12 and another part returns through an opening provided in the sheave 12, the opening being made of such a greatness that by a given speed ofthe film 1 (and consequently of the paddle wheel 9) as much quicksilver is drawn up under the sheave 12 as flows back. By increasing speed the sheave 12 will fall and by diminishing speed it will rise. By means of a projecting part 14 fixed on the shaft 13 is efiected that the sheave 12 cannot fall to the bottom of the chamber 8, and by a given speed of the pad- .where on the axis 16 a catch 17--is fixed capable to cooperate with the hook formed end of the arm 7. As easily to recognize, the arm 15 and the catch 17 form together a lever adapted to be actuated by the shaft '13.

By beginning the projection the bend lever 4 with the shutter 3 is so holden by hand that the opening 2 becomes free for the beam of light illuminating the film 1. Already after a. fewmoments of operation the paddle wheel 9 will have drawn up so much quicksilver under the sheave 12 that the latter falls and the catch 17 can engage with the hook formed end of the arm 7, thereby by means of the bent lever 4: preventing the shutter 4 to close the opening 2, If for any reason the film 1 stops and would consequently get ignited, the paddle wheel 9 will also stop thereby causing the sheave 12' and the catch 17 which is connected with it to rise, so that the end of the arm 7 becomes .free andthe shutter 3 will fall owing to the spring 6 hereby closing the opening 2, as sketched in Figure 1 in dotted lines.

Having thus described my invention, what I claim and desire to secure by Letters Pat-- cut is:

1. In a motion-picture projecting apparatus in combination, means for protecting the film against the beam of light, a reservoir, a fluid in the reservoir, a member adaptedto swim on the fluid and to engage with said means'for protectingthe film, a

device for drawing up fluid under the said member, means for reconducting to the reservoir, the fluid drawn up, I and means for driving the said drawing device.

2. In a motion-picture projecting apparatus in combination, means for protecting the film against the beam of light, a reservoir, a fluid in the reservoir, 21. member adapted to swim on the fluid and to engage with said means for protecting the film, a device for drawing up'fluid under the said member and for feeding it up as a weight on to the said member, means for reconducting to the reservoir the fluid drawn up and fed on, and means for driving the said drawing device.

3. In a,'m0ti0n-picture projecting apparatus in combination, means for protecting the film against the beam of light, a .reservoir, a fluid in the reservoir, a member adapted to swim on the fluid and to engage with saidmeans for protecting the film, a device for drawing up fluid under the said member and for feeding it up as a weight on to the said member, means for reconducting to the reservoir the fluid drawn up and fed on, and a film roll for driving the said drawing device.

4. In a motion-picture projecting appa-' ratus in combination, a shutter device for protecting the film against the beam of light, a reservoir, a-fluid in the reservoir, a member adapted to swim on the fluid and to engage with said shutter device, a device for drawing up fluid under the said member and for feeding it up as a weight on to the said member,- means forreconductit up as a weight on the said member, means for reconductmg tothe reservoir'the quicksilver drawn up and fedon, and means for driving the said drawing device.

6. In a motion-picture"projecting apparatus in combination, a's'hutter' device for protecting the filmagainst the beam of light, a reservoir, quicksilver in the reservoir, a member adapted to swim up the quicksilver and to engage with the said shutter device, a rotating paddle wheel for drawing up quicksilver under the said member and for feeding it up as'a weight on to the said member, means'for reconducting to the reservoir the quicksilver drawn up and fed on, and a film roll for driving the paddle wheel.

In testimony whereof I have signed my name to this specification.

MECHAU. v

In the presence of-- VIKTOR BENDER, O'rro WAeNnR. 

